Firefighters tackling the 3,300-acre Carson Midway Fire stumbled across more than 100 marijuana plants Saturday at an illegal grow house.

At 6 p.m. that night, Metro Vice, Narcotics and Intelligence and El Paso County Sherriff deputies searched the building, which is located in a rural area south of Fort Carson, and seized the plants, according to the sheriff’s office. Most of the plants were in the flowering stage and ready for harvest.

The sheriff’s office said no arrests were made and the investigation is ongoing.